Drop leaf table angular adjustment mechanism

ABSTRACT

This invention relates to a drop leaf table angular adjustment mechanism. The leaf and tabletop are pivotally connected with a hinge, in which a positioning ratchet plate with multiple angular positioning ratchet teeth to the underside of the tabletop hinge. On the rear of the leaf hinge set, there consists of a positioning plate with a curvature slot. The positioning ratchet plate and positioning plate are pivotally connected with a pivot bolt to form a mechanism for the providing the leaf angular lean adjustment. On the backside of the positioning plate there is a ladle-shape pawl on the downside of the positioning ratchet plate, wherein the pawl engages with any of the ratchet teeth of the positioning ratchet plate to obtain a relative stop position between the tabletop and leaf. The operation which releases the pawl from engagement can adjust the leaf to an arbitrarily lean angle adjustment.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to drop leaf table angular adjustment mechanism, which applies the inter-engagement of a positioning plate and hinge set at the bottom of the positioning ratchet plate. This mechanism provides the leaf to perform free limited lean-angle adjustments through the scope of the curvature slot of the positioning plate and pivot bolt which passes through. An engaged pawl and ratchet at the rear rim of the positioning plate is included to provide the table leaf multiple lean-angle adjustment and positioning functions.

(b) Description of the Prior Art

Most computer tables or desks are designed with a fixed pattern. When this type of table is to be moved or the objects placed on the table are rearranged, it requires a great deal of work and wasting of manpower. To resolve the above issues, some manufacturers have installed casters beneath the table. The casters have a locking device so that the user may move the table to a position and lock the casters to prevent the table from sliding.

However, the user of the types of desks or computer tables would usually place books or documents on the table surface for reading or convenience in viewing. In order to enhance stability, some manufacturers are known to add a drop leaf to the main tabletop to provide space for books and documents. Most of these leaves however are of a fixed design, which these leaves are unable to adjust with the visual height of the user. This implicitly affects the practical value and cannot be seen as an ideal design.

To resolve this type of issues, some manufacturers developed an adjustable angular leaf design, which however the angular positioning relies on a quite complicated mechanism. Not only is the adjustment difficult to operate, but also the stability is rather poor. It is indeed necessary to design an improved product with easier operation and stability.

SUMMARY OF THE INVENTION

Due to the existing defect in current drop-leaf tables, the inventor began in research and improvement based on the numerous years of experience and techniques to develop the drop leaf table angular adjustment mechanism of this present invention. The main purpose is by using a structural design to provide an even simpler structure for leaf angular adjustment, and at. the same time to enable the angular adjustment of the leaf to become even easier and convenient.

Another purpose of the invention purpose is to maintain an extremely firm and steady lean angle position of the leaf through structural assembly design, to avoid the issue of sudden dropping and ensure safeness.

In order to achieve the previous disclosed purposes, the structural design of the present invention mainly applies the inter-engagement of a positioning plate and hinge set at the bottom of the positioning ratchet plate. This mechanism provides the leaf to perform free limited lean-angle adjustments through the scope of the curvature slot of the positioning plate and pivot bolt which passes through. An engaged pawl and ratchet at the rear rim of the positioning plate is included to provide the table leaf multiple lean-angle adjustment and positioning functions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural view of the present invention in accordance with a preferred embodiment;

FIG. 2 is a local structural view of the above preferred embodiment;

FIG. 3 is a local structural view of the above preferred embodiment;

FIG. 4 is a structural view of the preferred embodiment with adjusting the leaf angle;

FIG. 5 is a structural view of the preferred embodiment at a different angle with adjusting the leaf angle;

FIG. 6 is a structural view of the preferred embodiment at another different angle with adjusting the leaf angle.

DESCRIPTION OF MAIN COMPONENT SYMBOLS  (1) Tabletop  (2) Hinge  (3) Leaf  (4) Stand  (5) Gate-leg  (6) Caster (10) Position ratchet plate (11) Vertical plate (12) Ratchet (13) Pivot hole (14) Pivot bolt (20) Positioning plate (21) Vertical plate (22) Curvature slot (23) Bolthole (24) Pivot bolt (25) Stop (30) Pawl (31) Pawl teeth (32) Lever rod (40) Spring positioner

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The previous description of the present invention and its other technological descriptions, characteristics and performances are described in detail with the drawings of a preferred embodiment.

Referring to the structural view in FIG. 1, the local structural view in FIG. 2, the structural exploded view in FIG. 3 and the structure views in FIGS. 4-6 are a preferred embodiment of the invention, the structural design of the movable table mainly consists of a tabletop (1), wherein the leaf (3) on the back of the tabletop (1) applies a hinge (2) set to perform lean angle adjustments. As the bottom of the tabletop (1) is an adjustable height stand (4), which the stand (4) is designed to have pre-determined number of gate-legs (5). A caster (6) is installed at the end of each gate-leg (5) to enable the product feature with mobile adjustment.

A positioning ratchet plate (10) is included at the predetermined positions beneath the hinge of the tabletop (1). The positioning ratchet plate (10) includes a vertical plate (11), which at the bottom rim of the vertical plate (11) includes a number of various angular positioning ratchets (12) and also a pivot hole (13) near the rear end of the vertical plate (11). In addition, a positioning plate (20) is included at the rear end of the hinge, in relatively to the said positioning ratchet plate (10) of the leaf (3). The positioning plate (20) also includes a vertical plate (21), in which the vertical plate (21) is located at the side of the vertical plate (11) of the said positioning ratchet plate (10). A curvature slot (22) is located on the vertical plate (21), allowing a pivot bolt (14) to pivotally connect the hinge set by passing through the pivot hole (13) of the ratchet vertical plate (11) and the curvature slot (22) of the positioning (20)vertical plate (21). This provides the leaf (3) to perform limited angular lean adjustments within the guided space of the curvature slot (22) and pivot bolt (14) of the positioning plate (20). In addition, a bolthole (23) is installed at the rear rim of the vertical plate (21) of the positioning plate (20), in which the said bolthole (23) pivotally connects with another pivot bolt (24) of a pawl (30). The pawl (30) is designed into a ladle-shape structure to simultaneously engage the positioning ratchet plate (10) and vertical plates (11) (21) of the positioning plate (20). At one end of the pawl (30) are pawl teeth (31) and on the other end includes a suitable hand-control lever rod (32). The hinge positioning plate (20) and bearing end of the pivot bolt (24) of the pawl (30) are installed with a spring positioner (40). The spring positioner (40) can be a torque spring embedded at the inner side of the pawl (30). The other end engages the stop (25) at the vertical plate (21) so that the pawl teeth (31) of the pawl (30) can engage with any of the ratchet (12) teeth of the previous positioning ratchet plate to maintain the position between the leaf (3) and tabletop (1). The above consists of the drop leaf table angular adjustment mechanism of this invention.

With the disclosed structure of the design, the mechanism applies a positioning plate (20), pawl (30) and pivot bolt (24) assembly of a spring positioner (40) to press the pawl (30) component. The pawl teeth (30) of the pawl (30) stops the tabletop (1) at the ratchet (12) positions of the positioning ratchet plate (10) so that the leaf (3) is unable to further conduct pivotal adjustment, and therefore the tabletop (1) and leaf (3) can obtain and maintain a firm position. The mechanism is particularly contributed by the ladle-shape of the pawl (30) component, in which the pawl (30) is capable to obtain a firm engagement position and support with the ratchet (12) of the positioning ratchet plate (10) to ensure that the leaf (3) will not occur with a sudden drop issue due to instant forces. When the angle of the leaf (3) intends to be adjusted, the user only requires to operate the control lever rod (32) attached to the pawl (30) component to allow the pawl teeth (31) of the pawl (30) to be released from the ratchet (12) teeth of the positioning ratchet plate (10). At the same time press, the spring positioner (40) accumulates a recover force for the hinge (2) between the tabletop (1) and leaf (3) to feature pivotal movement to arbitrarily adjust the leaf (3) to a suitable angle for the user. Once the pressing force of the lever rod (32) is released, the recover force of the spring positioner (40) is applied to push and resist the pawl (30) component so that the pawl (30) pawl teeth (31) are once again engaged in a ratchet (12) of the positioning ratchet plate (10). The process can achieve a firm position between the leaf (3) and tabletop (1).

It could be seen from above that the structural assembly design of the present invention which features adjustable leaf positions applies the inter-engagement of the pawl and spring positioner with the pivot connection of positioning ratchet plate and positioning plate of the tabletop and leaf to form a drop leaf table angular adjustment mechanism. Not only is the structural assembly simple, but also is extremely easy and convenient in operation. Most important is that the leaf and tabletop can maintain an extremely firm relative position relation to avoid sudden dropping due to external force or by the weight of objects. From an overall perspective view, the invention is deeply applicable to the industry and having practical safety.

In conclusion with the above description, it can be seen that the invention relates to the drop leaf table angular adjustment requirement for general desks, computer tables and other types of drop-leaf tables, wherein a simple and convenient drop leaf table angular adjustment mechanism design can provide firm position adjustment. The invention can effectively resolve the issue and defects of these types of tables for leaf angle adjustment. From an overall perspective view, the invention is deeply applicable to the industry, having practical value, and is an outstanding innovative design. 

1. A drop leaf table angular adjustment mechanism—comprising: a tabletop having a leaf and a hinge set at the back, wherein the said tabletop can be angularly adjusted using the hinge and the bottom of the tabletop having an adjustable height stand; a tabletop included with a positioning ratchet plate at the bottom of the hinge set and a positioning plate on the leaf at a relative position at the rear of the hinge set, said positioning ratchet plate and said positioning plate respectively including a vertical plate on the tabletop or the leaf, wherein the two vertical plates are inter-engaged into a pivot connection, the bottom rim of the said vertical plate of the positioning ratchet plate has a predetermined number of ratchets with a pivot hole, and said vertical plate of the positioning plate is included with a curvature slot; wherein a pivot bolt passes through the pivot hole of the positioning ratchet plate and a curvature slot of the positioning plate to form a pivot connection, wherein the leaf can perform angular lean adjustments within the limited scope of the positioning plate, the curvature slot and the pivot bolt; and a pivot bolt assembly having a pawl with a spring positioner included with the pivot bolt engaged between the positioning plate and the pawl, so that a pawl teeth at one end of the pawl engaging with any ratchet position of the positioning ratchet plate to maintain the position between the leaf and tabletop, wherein the handle control pawl frees the engagement of the pawl teeth with the ratchet of the positioning ratchet plate to provide an angular adjustment function with the leaf.
 2. The drop leaf table angular adjustment mechanism according to claim 1, wherein the pawl forms a ladle-shape to simultaneously engage the positioning ratchet plate and the bottom rim of the vertical plate of the positioning plate.
 3. The drop leaf table angular adjustment mechanism according to claim 1, wherein the pawl teeth at one end of the pawl engages with the ratchet of the positioning ratchet plate, and the other end of the pawl has a suitable hand-control lever rod.
 4. The drop leaf table angular adjustment mechanism according to claim 1, wherein a predetermined number of ratchet teethes are positioned at the bottom rim of the vertical plate of the ratchet plate to enable different angular positions.
 5. The drop leaf table angular adjustment mechanism according to claim 1, wherein a spring positioner is used as a torque spring. 